EP-A-0230910 discloses textile treatment compositions prepared by reacting C10-22-fatty acids with polyamines and neutralizing the reaction product with a non-oxidizing inorganic acid, where, as polyamine, aminoethylethanolamine, inter alia, and, as inorganic acid, phosphorous acid are preferred and are described in the examples. The acid is employed in a defined amount of from 0.7 to 1.3 acid equivalents per amine equivalent (EP-A-0230910, page 3, line 17), i.e. in an amount which is not sufficient to achieve an acidic pH for the dibasic phosphorous acid. If this acid is employed in such amounts that an acidic dispersion is formed, this dispersion is unstable and, on standing, soon separates into two phases of different concentration, which is unsuitable for practice (production, sale, storage and use). EP-A-0230910 also mentions good results with respect to odor on page 3, line 6. It should be commented in this respect that although phosphorous acid is itself odor-free, a strong disagreeable odor spreads under acidic conditions in the presence of the other products, which is also unsuitable for practice. Thus, for example, use in alkaline wash liquors or thereafter is mentioned on page 3, lines 34-35.
The principal object in EP-A-0230910 is to avoid discoloration or yellowing of textile material which is caused immediately after finishing, for example with a fabric softener, due to subsequent heat treatment, in particular due to thermosol treatment, as is usual for synthetic fibers, with the consequence that the heat-set material appears more yellowish or brownish.
However, an essentially different problem is yellowing which does not occur until some time after completion of the textile goods which have not yellowed due to the various treatment stages in their production, namely exclusively in jeans goods, which are essentially cellulose-containing (in general cotton-containing) fabrics which have been woven or knitted in a certain manner and dyed in a certain manner and may have been subjected to further treatment in a certain manner.
The fabrics used for jeans (denim fabrics) are generally made from dyed, usually warp-dyed, warp yam and undyed weft yam, which are usually woven or knitted in such a way that the dyed part predominates on the face side of the fabric, while the undyed part predominates on the reverse side of the fabric, for example by means of the twill weaving method (for example ⅓ or xc2xd) or by another weaving or knitting method which is suitable for this purpose. The dyeing is usually carried out using indigo dyes, such as, for example, Colour Index Vat Blue 1 or similar dyes. By means of various fading treatments, such as, for example, stonewashing, bleaching and/or washing, the jeans article can be given the known fashionable worn appearance. However, it has now been found that on storage the denim articles (jeans articles) treated in this way yellow over time, for example due to the action of constituents from the ambient air, such as ozone, nitrogen oxides, etc., especially in combination with daylight. Although the yellowing could be removed again from the made-up and yellowed goods by suitable washing, such washing processes are, however, normally not carried out by the ultimate retailer. Attempts have therefore been made to delay this yellowing effect by using certain finishing compositions, but the undesired yellowing occurs after a certain time which is relatively short for storage and/or sales purposes. There is therefore a wish to employ compositions which have a stronger or longer yellowing-inhibiting action so that the goods can be stored and/or displayed for a longer time without yellowing damage and can be offered for sale in perfect condition.
It has now been found that a surprisingly good improvement in the yellowing-inhibiting action against this storage yellowing on jeans goods can be achieved using the phosphates defined below, from salt formation of the defined amino compounds with at least 1.5 equivalents of ortho-phosphoric acid per equivalent of basic amino groups, whose dispersions are very stable even under acidic conditions.
The invention relates to the use of the defined phosphates for inhibiting said yellowing and to the process for yellowing-inhibiting finishing therewith.
The invention thus provides a process for the yellowing-inhibiting finishing of textile, indigo-dyed, washed and/or stonewashed and/or bleached denim articles which is characterized in that the finishing is carried out from aqueous medium with protonated fatty acid ester-aminoamides and/or hydroxyaminoamides of N-(xcex2-hydroxyethyl)ethylenediamine in which the fatty acid radicals each contain from 12 to 22 carbon atoms and which have been protonated with at least 1.5 equivalents of ortho-phosphoric acid per equivalent of basic amino groups.
The protonated fatty acid ester-aminoamides and/or hydroxyaminoamides to be employed in accordance with the invention are advantageously employed in the form of protonated condensates of the said C12-22-fatty acids with N-(xcex2-hydroxyethyl)ethylenediamine.
Suitable fatty acids are any desired, preferably linear fatty acids having 12 to 22 carbon atoms which are conventional per se, preferably saturated fatty acids, for example lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid and behenic acid. Both individual acids and technical-grade acids (acid mixtures), such as, for example, hydrogenated tallow fatty acid, can be employed. Of the said acids, those having from 14 to 18 carbon atoms, and also technical-grade mixtures of such acids, are preferred.
The condensates [i.e. products of the acylation of N-(xcex2-hydroxyethyl)ethylenediamine] can be prepared in a manner known per se by condensation of the said fatty acids with N-(xcex2-hydroxyethyl)ethylenediamine under water-eliminating conditions. For their preparation, from 1 to 2.5 mol, preferably from 1.2 to 2.2 mol, in particular from 1.4 to 2 mol, of fatty acid are advantageously employed per mole of N-(xcex2-hydroxyethyl)ethylenediamine. The condensation is advantageously carried out in an anhydrous medium, most simply in the absence of solvents, for example at temperatures in the range from 140 to 220xc2x0 C., advantageously under an inert atmosphere (for example under nitrogen) and/or optionally under reduced pressure. In addition to the above-mentioned monoamides, the said condensates may optionally, depending on the molar ratio and condensation conditions, contain further amides, namely diamides, i.e. at least one fatty acid diamide and/or at least one fatty acid ester diamide of N-(xcex2-hydroxyethyl)ethylenediamine. Besides the amide groups, the acylation product prepared in this wayxe2x80x94referred to below as xe2x80x9caminocondensatexe2x80x9dxe2x80x94contains basic amino groups, which are now at least partially protonated with phosphoric acid to give the corresponding aminocondensate-phosphoric acid salt. The proportion of protonatable basic amino groups in the aminocondensate can be determined by measuring the amine number. The amine number is advantageously in the range from 30 to 100 mg, preferably from 50 to 70 mg, of KOH per g of aminocondensate. From 0.5 to 1.1 mol, preferably from 0.8 to 1 mol, of phosphoric acid are advantageously employed per mole-equivalent of basic amino groups (or amino nitrogen) in the aminocondensate.
The phosphoric acid is advantageously employed in the form of an aqueous solution, for examplexe2x80x94calculated as ortho-phosphoric acid H3PO4xe2x80x94as a 1 to 10% by weight solution.
It is advantageous to add a hydrophilic, nonionogenic surfactant, preferably having an HLB of  greater than 12, for example a product of the addition of from 10 to 70 mol, preferably from 25 to 60 mol, of ethylene oxide onto 1 mol of C9-24-fatty alcohol. Suitable fatty alcohols are any desired, preferably saturated alcohols having 9 to 24 carbon atoms, preferably 11 to 18 carbon atoms, which are conventional per se; for example, linear fatty alcohols, such as lauryl alcohol, myristyl alcohol, cetyl alcohol or stearyl alcohol, or branched fatty alcohols, such as synthesis alcohols, for example having 9 to 15 carbon atoms, preferably 11 to 15 carbon atoms, can be employed. From 1 to 30 parts by weight, preferably from 2 to 15 parts by weight, of surfactant are advantageously employed per 100 parts by weight of aminocondensate-phosphoric acid salt. In accordance with an advantageous procedure, the nonionogenic surfactant is mixed with the aminocondensate before the addition of the phosphoric acid, and the mixture is then advantageously added, preferably as a melt, to the aqueous phosphoric acid. The amount of water in the aqueous phosphoric acid is advantageously selected so that the concentration of aminocondensate-phosphoric acid salt in the aqueous preparation is in the range from 5 to 40% by weight, preferably from 10 to 30% by weight. The pH of the aqueous dispersions corresponds to the amounts of the components employed, particularly of the phosphoric acid, and is principally xe2x89xa66 in these dispersions, advantageously in the range from 2 to 6, preferably from 2 to 4.5, in particular from 2.5 to 4.5. The term xe2x80x9caminocondensate-phosphoric acid saltxe2x80x9d here is taken to mean the above-described product of the reaction of phosphoric acid with the entire aminocondensate.
The above-mentioned fatty acid ester-aminoamides and/or fatty acid hydroxyaminoamides protonated with phosphoric acid, advantageously in the form of the protonated aminocondensates mentioned, preferably as aqueous formulations as described, can be employed for final finishing for yellowing inhibition.
The substrates are generally made-up articles (jeans goods) produced from indigo-dyed denim fabric which have been faded by conventional treatment known per se, in particular by washing and/or stonewashing (generally with pumice stones) and/or bleaching to give the typical jeans look.
Suitable dyes for dying the warp yarn are the known vat dyes from the indigo series, principally blue dyes, and optionally also indigo-like sulfur dyes, the latter, for example, in combination with blue vat dyes from the indigo series. For weaving or knitting, the yarns are generally sized, so that the made-up goods usually still contain the sizing agent before the said fading. For making-up, the fabric is optionally finished with a lubricant, for example a sewability improver. These auxiliaries can be removed, for example by washing, during the fading treatment.
The made-up denim goods can be faded using known processes, auxiliaries and machinesxe2x80x94by washing and/or stonewashing and/or bleaching.
For washing, use can be made of known detergents, for example anionic or nonionogenic detergents. If desired, an enzymatic hydrolytic treatment, for example with hydrolases (for example cellulases) can be carried out at the same time. If an enzymatic treatment is carried out at the same time, it is advantageous to employ nonionogenic detergents, for example optionally end-capped products of the addition of ethylene oxide and optionally propylene oxide onto high-molecular-weight fatty alcohols, principally products of the addition of from 5 to 50 mol of ethylene oxide and optionally propylene oxide (where ethylene oxide is preferably preponderant) onto one mol of C9-18-fatty alcohol.
For washing, use can be made, if desired, of additives as can be employed for desizing, for example sequestrantsxe2x80x94for example polycarboxylic acids, such as polyacrylic acids, and combinations thereof with saccharides, or non-polymeric polycarboxylic acids, such as, for example, citric acid, gluconic acid, NTA or EDTAxe2x80x94and/or enzymes (for example xcex1-amylases or cellulases)xe2x80x94as can, as is known, be employed as biocatalysts for desizing. Such sequestrants are described, for example, in EP-A 0465286, 0465287 and 0433010; suitable enzymes are described, for example, in xe2x80x9cTextilbetriebxe2x80x9d 1983/07, Volume 101, page 44.
After the desizing, a stonewashing process can be inserted if desired, optionally in combination with an enzymatic hydrolytic treatment. For the stonewashing, use can be made of stonewashing agents known per se, principally pumice stones or additives with an analogous action.
After the desizing and/or after the stonewashing, a washing process can, if desired, be carried out for anti back-staining or in order to remove stonewashing residues.
The washing process and/or the stonewashing process and, if desired, the hydrolysis process and/or washing process can if desired be repeated a number of times in order to increase the effect.
For the bleaching, use can be made of known bleaches, for example oxidants, reducing agents and/or enzymes.
For oxidative bleaching, known oxidizing bleaches, for example chlorine, e.g. in the form of hypochlorite (most simply in the form of KClO, for example as Javelle water), or peroxides, such as, for example, hydrogen peroxide, or other per compounds, such as, for example, potassium permanganate, or with suitable enzymes, are suitable.
For reductive bleaching, any desired reducing agents as usually employed for reducing vat dyes to the leuko form, for example reducing saccharides, principally aldoses, for example mono- and oligosaccharides, are generally suitable.
The said treatments by washing and/or stonewashing and/or bleaching can be carried out in one or more steps and/or repetitions. In general, from two to six, preferably three or four treatments, which may be identical or different, are carried out in industry. Thus, for example, washing (desizing) can be carried out in a first step, and bleaching, for example with or without enzymatic treatment, can be carried out in one or more subsequent steps. Stonewashing treatment, for example with pumice stones, can be carried out in any desired one of these treatment steps, preferably together with cellulases.
After the last of these treatment steps, the final treatment according to the invention with the above-defined aminocondensate-phosphoric acid salt can be carried out in the same sequence and in the same apparatus. The treatment according to the invention with the above-defined aminocondensate-phosphoric acid salts is advantageously carried out by exhaust processes from an aqueous medium, for example with a liquor ratio as also used for the preceding treatments, for example from 4:1 to 30:1, preferably from 6:1 to 20:1, where the aminocondensate-phosphoric acid salts are preferably employed in the form of aqueous dispersions as described above. The aminocondensate-phosphoric acid salts are advantageously employed in suitable concentrations, based on the substrate, preferably in a concentration in the range from 0.02 to 4% by weight, particularly preferably from 0.1 to 2% by weight, based on the dry substrate. The treatment can be carried out under conditions which are conventional per se, for example in the temperature range from 15 to 95xc2x0 C., preferably from 30 to 60xc2x0 C., and at pH values in the acidic to weakly alkaline region, for example at a pH in the range from 3 to 8, advantageously at a pH in the range from 3 to 7, preferably from 4 to 7; in general, acidic pH values, i.e. pH  less than 7, are preferred. The pH can be set using acids, bases and/or buffers known per se, for example using phosphoric acid, acetic acid, sodium carbonate and/or or phosphoric acid mono- or disodium salt. The treatment duration can be varied as desired and is generally selected corresponding to the substrate, the apparatus used, the product employed and the desired effect, for example in the range from 10 minutes to 1 hour, preferably from 15 minutes to 30 minutes, after which the treated goods can be removed from the machine and dried in a suitable manner, for example in a drying drum (tumbler), for example at from 40 to 80xc2x0 C., or in air.
The jeans articles treated in this way are distinguished by surprisingly good and long resistance to yellowing, as caused, in particular, by air components (ozone, nitrogen oxides, etc.), especially with simultaneous action of daylight.
In the examples below, parts are by weight and percentages are percent by weight; the temperatures are given in degrees Celsius. xe2x80x9cC.I.xe2x80x9d stands for xe2x80x9cColour Indexxe2x80x9d, xe2x80x9ckNUxe2x80x9d stands for xe2x80x9ckiloNOVO unitsxe2x80x9d and xe2x80x9cGTUxe2x80x9d stands for GENENCOR textile unitsxe2x80x9d.